Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 56. (Budapest 1964)

Csalogovits, J. I.: The non-magnetic derivation of Atlantic and Mediterranean rock-provinces and their connection with orogenic metamorphism

For types under A the absence of water containing minerals is characteristic, when considering both the leucratic and melanocratic components. For types under B, however, the presence of water containing minerals is characteristic in the leucratic and melanocratic components. As a second step of correlation reckoning we have made separate calculations by dividing the rocks into two types. The correlation of the A-type (Na

2

0

—H

2

0) is weak (r

HA

=0,15; r

s

=0,42). That of the B-type, however, rather strong (r

HA =0,81; r

s

=0,92) that is to say the Na

2

0 —H

2

0 stochastic function relation almost functional (!) If the average formation depth (after EVANS) applied to D abscissa, we obtain a e"

XD-type curve*, according to the expected correlation. If, however, the D value is not interpreted as a depth pressure (static pressure) but as a dynamic pressure which may be assumed to be present in orogenic systems, then we obtain the zeolite (lugarite) type of the palogene Atlantic type of magmatites being syngenetic with the orogenic compaction of pelites, in which the Na

2

0

— H

2

0 system pressed into the melt forms a separate zeolitic phase, and the later crystallisations of coloured minerals also saturate on Na

—H

2

0. If we extract of these rocks the contents of zeolite, the maphitic Na as well as the water, we obtain the Pacific basalt composition, that is to say the primary melt composition of the rocks. The alteration of the regressive index tends to show that the variation of the unit Na by the increasing pressure (D

(P)

) goes hand in hand with a change of the water contents having a decreasing quantity, or else towards higher pressures, in proportion with b coefficients, the variation of the Na-contents becomes independent from the water contents (Fig. 1). The migration of alkalis in already dehydrated metamorphite systems being under a higher pressure, shows already an effect in the reverse sense. Reason of this may be found in the opposed proportion of the Na and K-ion as well as the hydrated ion radii. D.S. KORSINSKY and E. SZÁDECZKY-KARDOSS have pointed to this phenomenon. If, namely, on basis of the known ion-measure correlation the ion-migrations V

k and V

Na

, according to non-hydrated radii, and W

k and W

Na migration speed according to hydrated radii and the rate of migration speed is dependent on the radius-rate, in that case if W

Na

>W

k then V

Na

<V

k because R

N

aH

2

o > R

KH

2

O From the above it follows that the character of an Atlantic resp. Mediterranean alcalinity changes in course of the metamorphisation, with theever increasing pressure in the components transmitted by metamorphites i. e. r A = alkaline migration coefficient A = e

_X2D(p) decreases in form, that is to L

k say A-1 = —-^- A

_1 = e

X

2

D(P) increases in form with the increase of pressure resp. ^Na time. (C

Na resp. C

K are the concentration variations of alkaline migrations belonging to the respective time and pressure state). * The alteration of formation depth value does not change the exponential type of the curve, only the value of the coefficient changes.